Like the fellow code:<br><br>&nbsp; (= 1 1 t) ; error<br>&nbsp; (= 1 2 t) ; nil<br><br>t is a symbol, (= 1 1 t) signal a error, that is what we expect. <br>But in the second form there is no error, because&nbsp; "=" get the<br>result before to eval the third argument "t". <br>So "=" not to eval all arguments, that is&nbsp; a "sepecial form" activation.<br><div><div><br></div><div><br></div><div style="font-size: 12px;font-family: Arial Narrow;padding:2px 0 2px 0;">------------------&nbsp;原始邮件&nbsp;------------------</div><div style="font-size: 12px;background:#efefef;padding:8px;"><div><b>发件人:</b>&nbsp;"Andreas Schwab";&lt;schwab@linux-m68k.org&gt;;</div><div><b>发送时间:</b>&nbsp;2017年4月24日(星期一) 下午5:59</div><div><b>收件人:</b>&nbsp;"zhangjg"&lt;jinguozhang@qq.com&gt;; <wbr></div><div><b>抄送:</b>&nbsp;"26635"&lt;26635@debbugs.gnu.org&gt;; <wbr></div><div><b>主题:</b>&nbsp;Re: bug#26635: 25.1; elisp docs bug</div></div><div><br></div>On Apr 24 2017, "zhangjg" &lt;jinguozhang@qq.com&gt; wrote:<br><br>&gt; In session "3.4 Comparison of Numbers", "=" is a set to a "function" but, in fact it a "special forms".<br><br>Why do you think `=' is a special form?<br><br>Andreas.<br><br>-- <br>Andreas Schwab, schwab@linux-m68k.org<br>GPG Key fingerprint = 58CA 54C7 6D53 942B 1756&nbsp; 01D3 44D5 214B 8276 4ED5<br>"And now for something completely different."</div>